Soilproofing tennis balls



FIP8309 UHlIVlu vn sir? UNITED STATES Search iioon PATENT OFFICE SOILPROOFING TENNIS BALLS assignments, to A. G.

Spalding & Bros. Inc., a

corporation of Delaware No Drawing. Application May 13, 1937, Serial No. 142,494

5 Claims.

This invention relates to the treatment of fabrics, and articles resulting therefrom. The invention relates further to the treatment of articles of manufacture having exterior surface material containing animal fibers, such as hair, and more particularly wool, which treatment renders the material less susceptible to discoloration while in use.

Balls usedi/in' tennis games-strike the. courts, ground,xetc. 'andbecome soiled, thereby lessening visibility of the balls in play, detracting from the appearance, and reducing the pleasure of playing with the balls, since they become dirty and oldlooking. A ball which retains its original appearance when new is highly desirable from the player's standpoint.

Articles such as tennis balls having exterior surface material containing Wool fibers which in actual use come into contact with soil, when treated by the process of the present invention do not readily become discolored by the soil. It may be stated at this point that the term soil herein includes within its scope any dirt and dust or the like with which an article such as a tennis ball is likely to come in contact; the term soilproof is intended to indicate a decrease in the tendency of a material to become discolored by soil, as well as freedom of the tendency to become so discolored.

We have found that by treating wool fabric in such a manner as to affect the fiber as for instance particularly by chemically changing the surfaces of the wool fibers, a highly desirable soilproofing effect is obtained. Bleaching agents or oxidizing agents such as hydrogen peroxide, chlorine, potassium permanganate, and sodium peroxide have this effect. Of these, hydrogen peroxide is preferred since the other compounds mentioned tend to discolor the wool. This discoloration may, however, be removed, if desired, by further treatment with a solution of hydrogen peroxide which may be a weak solution such as a 3% solution used in ordinary bleaching processes.

In imparting soilproofing qualities to wool by means of a bleaching agent such as those mentioned above, the reaction of the agent on the wool is carried appreciably further than is necessary in ordinary bleaching. Bleached wool obtained in ordinary bleaching processes is not soilproof. To determine this, soilproofing tests can be readily carried out with tennis balls, for instance, by tumbling the balls in a mixture of gravel, dirt, etc. Balls treated by the process of the present invention, and ordinary balls not treated thereby, show very decided diiferences in the amount of soiling of the balls. It is also found that the soilproofed balls are readily cleaned by simply washing with soap and water, or with water alone.

A difference between the chemical constitution. of untreated wool or wool that has been bleached by ordinary bleaching processes, and wool that has been soilproofed can be detected by means of the biuret test. In this test, a pink, reddish violet or violet color is obtained by treatment of the soilproofed wool with caustic alkali and copper sulphate. For testing tennis ball felt, a drop of 20% potassium hydroxide is placed on a felt sample and, if Wetting does not take place readily, it is rubbed gently with a stirring rod to facilitate wetting. A drop of 1% copper sulphate solution is then added to the area covered by the alkali solution. The rapidity of formation of the color and the depth thereof indicate the degree of soilproofing. No positive reaction is obtained in a test on untreated wool or wool that has been treated by ordinary bleaching processes. Wool treated by ordinary bleaching processes will at most yield a slight color only after a considerable time.

Another indication of the chemical difference between soilproofed wool and that which is not soilproof is the greatly increased afiinity of the treated wool for both acid and basic dyes. The treated wool also does not yellow as rapidly in nitric acid.

Microscopic examinations of wool fibers treated by the process of the present invention indicate a difference between such fibers and fibers not so treated. Cross-sections of fibers treated in hydrogen peroxide, chlorine water and potassium permanganate solution were prepared and. stained with methylene blue, and then examined under the microscope. The methylene blue colors the affected parts of a fiber more than any unaffected parts. It was noted that fibers treated with hydrogen peroxide were stained uniformly all the way through and did not show any evidence of a mere surface treatment. The fibers treated with chlorine water and potassium permanganate, in each instance were stained more deeply nearer the surface. In other words, a dark blue ring extended inward from the surface. In the case of the chlorine treated fibers, varying degrees of treatment changed the thickness of the stained ring. Although there may be a diiference in the manner in which the different reagents act on the wool the soilproofing effects are noted.

Solutions of sodium hydroxide and the like produce a certain amount of soilproofing. Bleaching agents such as those named above are preferred, however, to hydroxide solutions.

By way of illustrating the process of the present invention, the following example may be given: A tennis ball of the type comprising a rubber compounded center and a Wool fabricated cover cemented or adhered to the center is dipped in a 30% hydrogen peroxide solution (about 13% available oxygen) long enough to Wet the cover thoroughly. The peroxide solution is permitted to drain off for about five minutes. The ball is then preferably immersed in a 5% ammonium hydroxide solution.

Treatment with ammonia solution is not absolutely essential to the process. It may or may not be employed subsequent to treatment with hydrogen peroxide. In either case, an article after treatment is dried at temperatures that may range from room temperature to about 180 F. No further treatment is needed. One advantage of the process employed in the foregoing example is that in view of the volatility of the agents used, nothing is left in the wool that must be Washed out.

In the use of ammonia after the peroxide treatment, there is a. considerable reduction in liquid held in the fabric, and thus drying of the fabric is greatly aided. One explanation of this is that the ammonia effects a liberation of gas which expels liquid from the surface of the fabric. Another explanation is that the ammonia efiects some change in surface tension which permits better drainage. Besides assisting in drying, the

ammonia assists to some extent in bleaching.

for instance, tennis balls were found tobe soilproof after treatment with a saturated solution of chlorine in water at about 25 C. for about five minutes, and then drying them at about 40 C. Aside from the yellow color produced by the chlorine the balls were about as soilproof as those treated with hydrogen peroxide. As stated above, this yellow color can be removed by treatment with an ordinary bleaching solution of hydrogen peroxide.

In the use of potassium permanganate, tennis balls were treated with about a 1% solution of the permanganate for about 1 minute. The dark brown color produced on the cover of the balls was changed by soaking the balls in a 2% solution of hydrogen peroxide. The balls were then dried at about C. Treatment with potassium permanganate resulted in a less soilproof article than treatment with hydrogen peroxide.

By dipping tennis balls in a 10% solution of sodium peroxide for about one minute and then drying them at room temperature, except for the color, the results were about the same as in the soilproofing treatment with hydrogen peroxide.

A wetting agent is preferably mixed with the soilproofing agent since it assists greatly in the uniform penetration of the soilproofing agent into the fabric treated. Residual amounts of the wetting agent left on the fabric help in the subsequent washing of a fabric. It is noted that the wetting agent has some soilproofing efiect when used without the peroxide treatment. A wetting agent such as sodium-lauryl-sulfate, or sodium hexadecylsulfonate, may be used in suitable proportions in the soilproofing agent. For instance, about 1.5 pounds of sodium-lauryl-sulfate in about forty gallons (U. S. measure) of peroxide solution has been found satisfactory.

It has been found preferable in the manufacture of tennis balls to treat them by the present soilproofing process after the felt or melton cover has been attached to the center, or, in other words, after assembly of a ball and after vulcanization. Balls made from fabric previously treated by the present process are not as soilproof as balls treated after the cover is applied and which therefore were not subjected to the heating in the covering press.

Wool fabric subjected to the treatment of the present process has a rather hard, harsh feel and other properties which render it particularly useful as tennis ball covering. The wool is resistant to wear and remains surprisingly clean when subjected to the action of dirt. Other textile fibers besides wool that may be treated to render them soilproof are hair fibers, such as rabbit fur (useful in making hats), alpaca, mohair, camel hair, and the like.

We claim:

1. In a method of soilproofing tennis balls, or the like articles, having exterior surface material normally subject to discoloration by contact with soil, the said material containing wool fibers; contacting the said material with an oxidizing bleaching agent to decrease the tendency of the said material to become discolored by soil.

2. In a method of soilproofing tennis balls, or the like articles, having exterior surface material normally subject to discoloration by contact with soil, the said material containing wool fibers; contacting the said material with hydrogen peroxide to decrease the tendency of the said material to become discolored by soil.

3. In a method of soilproofing tennis balls, or the like articles, having exterior surface material normally subject to discoloration by contact with soil, the said material containing wool fibers; contacting the said material with chlorine to decrease the tendency of the said material to become discolored by soil,

4. In a method of soilproofing tennis balls, or the like articles, having exterior surface material normally subject to discoloration by contact with soil, the said material containing wool fibers; contacting the said material with potassium permanganate to decrease the tendency of the said material to become discolored by soil.

5. Steps in a method of treating tennis balls having a fabric cover containing animal fibers, comprising treating a tennis ball with hydrogen peroxide solution and thereafter treating the ball with ammonia solution to thereby render the cover soilproof.

JOHN BERNARD DICKSON. JOHN HERMAN. 

